Bona of Savoy, Duchess of Milan (10 August 1449 – 23 November 1503) was the second spouse of Galeazzo Maria Sforza, Duke of Milan and a member of the noble Italian House of Savoy. She served as regent of Milan during the minority of her son 1476–1481.

In 1464, Bona was to have been betrothed to Edward IV of England, until his secret marriage to Elizabeth Woodville was revealed. She married Galeazzo Maria Sforza on 9 May 1468. An alliance between the Sforza and the royal house of France had been rumoured from as early as 1460, and "in June 1464 Bona of Savoy was officially offered to Galeazzo by letters from the King of France and the Duke of Savoy." The union produced four children:

Bona's husband was assassinated, on 26 December 1476 at the age of 32 by three young noblemen on the porch of the cathedral church of San Stefano in Milan. Galeazzo was succeeded after his 10-year reign by his 7-year-old son Gian Galeazzo Sforza (1469–1494) under the regency of Bona. But dissensions soon arose between the regent and her brother-in-law, Ludovico Maria Sforza, nicknamed "Il Moro" (the Moor).

In the first encounter Bona and her chief counsellor, Cicco Simonetta, were victorious, and Ludovico and his brothers were made to leave the city. In order to obtain his re-admission, Ludovico, took advantage of the rivalry between Tassino (the favourite of Bona) and Simonetta. The fall and execution of Simonetta followed. From 1479 the real government of Milan lay in the hands of Ludovico, whose power was further secured in 1480, when he seized his nephew Gian, deprived him of the duchy and assumed control. Consequently, Bona was obliged to leave Milan and Ludovico was left to rule unchallenged.[1]

Bona of Savoy commissioned the Sforza Book of Hours manuscript, which was painted in about 1490 by a famous court artist, Giovan Pietro Birago. She used the book, which contained devotional texts and is considered to be one of the most outstanding treasures of the Italian Renaissance.[2]